function GVerify (options) { // 创建一个图形验证码对象，接收options对象为参数
    this.options = { // 默认options参数值
        id: '', // 容器Id
        canvasId: 'verifyCanvas', // canvas的ID
        width: '80', // 默认canvas宽度
        height: '40', // 默认canvas高度
        type: 'number', // 图形验证码默认类型blend:数字字母混合类型、number:纯数字、letter:纯字母
        code: ''
    }

    if (Object.prototype.toString.call(options) === '[object Object]') { // 判断传入参数类型
        for (var i in options) { // 根据传入的参数，修改默认参数值
            this.options[i] = options[i]
        }
    } else {
        this.options.id = options
    }

    this.options.numArr = '1,2,3,4,5,6,7,8,9,Z,X,C,V,B,N,M,A,S,D,F,G,H,J,K,L,Q,W,E,R,T,Y,U,P'.split(',')
    this.options.letterArr = getAllLetter()
    this._init()
    this.refresh()
}

GVerify.prototype = {
    /** 版本号**/
    version: '1.0.0',

    /** 初始化方法**/
    _init: function () {
        var con = document.getElementById(this.options.id)
        var canvas = document.createElement('canvas')
        // this.options.width = con.offsetWidth > 0 ? con.offsetWidth : '30'
        // this.options.height = con.offsetHeight > 0 ? con.offsetHeight : '30'
        this.options.width = '90'
        this.options.height = '30'
        canvas.id = this.options.canvasId
        canvas.width = this.options.width
        canvas.height = this.options.height
        canvas.style.cursor = 'pointer'
        canvas.innerHTML = '您的浏览器版本不支持canvas'
        con.appendChild(canvas)
        var parent = this
        canvas.onclick = function () {
            parent.refresh()
        }
    },

    /** 生成验证码**/
    refresh: function () {
        var canvas = document.getElementById(this.options.canvasId)
        if (canvas.getContext) {
            var ctx = canvas.getContext('2d')
        }
        ctx.textBaseline = 'middle'

        ctx.fillStyle = randomColor(180, 240)
        ctx.fillRect(0, 0, this.options.width, this.options.height)

        if (this.options.type === 'blend') { // 判断验证码类型
            var txtArr = this.options.numArr.concat(this.options.letterArr)
        } else if (this.options.type === 'number') {
            var txtArr = this.options.numArr
        } else {
            var txtArr = this.options.letterArr
        }

        this.options.code = ""
        for (var i = 1; i <= 4; i++) {
            var txt = txtArr[randomNum(0, txtArr.length)]
            this.options.code += txt
            // ctx.font = randomNum(this.options.height / 2, this.options.height) + 'px SimHei' // 随机生成字体大小
            ctx.font = '22px SimHei'
            ctx.fillStyle = randomColor(50, 160) // 随机生成字体颜色
            ctx.shadowOffsetX = randomNum(-3, 3)
            ctx.shadowOffsetY = randomNum(-3, 3)
            ctx.shadowBlur = randomNum(-3, 3)
            ctx.shadowColor = 'rgba(0, 0, 0, 0.3)'
            var x = this.options.width / 5 * i
            var y = this.options.height / 2
            var deg = randomNum(-30, 30)
            /** 设置旋转角度和坐标原点**/
            ctx.translate(x, y)
            ctx.rotate(deg * Math.PI / 180)
            ctx.fillText(txt, 0, 0)
            /** 恢复旋转角度和坐标原点**/
            ctx.rotate(-deg * Math.PI / 180)
            ctx.translate(-x, -y)
        }
        /** 绘制干扰线**/
        /* for (var i = 0; i < 4; i++) {
         ctx.strokeStyle = randomColor(40, 180)
         ctx.beginPath()
         ctx.moveTo(randomNum(0, this.options.width), randomNum(0, this.options.height))
         ctx.lineTo(randomNum(0, this.options.width), randomNum(0, this.options.height))
         ctx.stroke()
        } */
        /** 绘制干扰点**/
        /* for (var i = 0; i < this.options.width / 4; i++) {
         ctx.fillStyle = randomColor(0, 255)
         ctx.beginPath()
         ctx.arc(randomNum(0, this.options.width), randomNum(0, this.options.height), 1, 0, 2 * Math.PI)
         ctx.fill()
        } */
    },

    /** 验证验证码**/
    validate: function (code) {
        var code = code.toLowerCase()
        var v_code = this.options.code.toLowerCase()
        if (code == v_code) {
            return true
        } else {
            return false
        }
    }
}
/** 生成字母数组**/
function getAllLetter () {
    var letterStr = 'a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z'
    return letterStr.split(',')
}
/** 生成一个随机数**/
function randomNum (min, max) {
    return Math.floor(Math.random() * (max - min) + min)
}
/** 生成一个随机色**/
function randomColor (min, max) {
    var r = randomNum(min, max)
    var g = randomNum(min, max)
    var b = randomNum(min, max)
    return 'rgb(' + r + ',' + g + ',' + b + ')'
}

export {
    GVerify
}
